Unless otherwise indicated herein, the materials described herein are not prior art to the claims in the present application and are not admitted to be prior art by inclusion in this section.
Polarization splitter rotators (PSR) can be useful components for a photonic integrated circuit (PIC) on both Si and Si/SiN hybrid platforms. Integrated optical devices and circuits are often polarization sensitive, and usually designed for TE mode only. As such, the TM mode of the input light may be converted to the TE mode. Polarization insensitive circuits can use a high performance PSR to split and rotate a combination of TE/TM input light to TE light only.
Often, the light that is input can include both the TM mode and TE mode, but when coupled to a PIC, the TE mode is preferred. The TE and TM are split and the TM is converted to TE and both are provided to identical devices that operate with the same polarization.
Previously, PSR devices may have included Si/SiN hybrid platforms, with a Si substrate having a SiO2 region thereover, with the SiO2 region having a SiN waveguide separate from a Si waveguide (optically coupled by the SiO2). In one option, the TM mode can be split from the TE mode and then subsequently rotated to transform the split TM mode to a TE mode. Another option converts the TM mode to a higher mode TE (TE01) in a polarization rotation device (PR) with the conversion in a rib waveguide structure, splits the TE01 from the TE in a polarization splitter (PS), and then converts the TE01 to TE00 in a second waveguide. However, these approaches have limited fabrication tolerance, a small bandwidth, and a low extinction ratio due to the complex mode conversion and design, which may be unfavorable.
The subject matter claimed herein is not limited to implementations that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one example of a technology area where some implementations described herein may be practiced.